Search results for "Averaging"
showing 10 items of 47 documents
Ensemble Averaging and Multiple Statistical Testing of EMG Activities of Cyclically Repeated Body Motions. A Tool for Muscle Function Analysis in Exp…
2003
Coupled with suitable computerized signal recording and processing methods surface electromyography can be a powerful tool for the analysis of muscle activity in specific body movements. It can be used for this purpose in experimental and in clinical diagnostic orthopaedics as well as in physiotherapy. We describe in this paper a motion analysis system comprising this feature. It has been employed for the diagnosis of the basic angular kinematics and muscle function in human gait and other cyclically repeatable movements of the human locomotive system. Changes in the temporal characteristics of the movements and the muscle activity due to changed physical or experimental conditions can be s…
SPECIAL SPLINES OF HYPERBOLIC TYPE FOR THE SOLUTIONS OF HEAT AND MASS TRANSFER 3-D PROBLEMS IN POROUS MULTI-LAYERED AXIAL SYMMETRY DOMAIN
2017
In this paper we study the problem of the diffusion of one substance through the pores of a porous multi layered material which may absorb and immobilize some of the diffusing substances with the evolution or absorption of heat. As an example we consider circular cross section wood-block with two layers in the radial direction. We consider the transfer of heat process. We derive the system of two partial differential equations (PDEs) - one expressing the rate of change of concentration of water vapour in the air spaces and the other - the rate of change of temperature in every layer. The approximation of corresponding initial boundary value problem of the system of PDEs is based on the cons…
Probing slow fluctuations in nonergodic systems: Interleaved sampling technique
2007
We present a new dynamic light scattering scheme to obtain ensemble-averaged correlation functions of slow fluctuations in non-ergodic systems in an efficient way. On a rotating sample, a large set of separate correlation functions is measured in parallel, for each independent orientational component of the sample’ density fluctuations. The ensemble-averaged correlation function spans a lag time range from 1 to 104 s. We describe our first implementation of this technique, discuss its statistical accuracy and show first results. Compared to plain ensemble averaging over a series of N measurements, the total measurement time is usualy reduced by a factor N without significant degradation of …
SPECIAL HPERBOLIC TYPE APPROXIMATION FOR SOLVING OF 3-D TWO LAYER STATIONARY DIFFUSION PROBLEM
2019
In this paper we examine the conservative averaging method (CAM) along the vertical z-coordinate for solving the 3-D boundary-value 2 layers diffusion problem. The special parabolic and hyperbolic type approximation (splines), that interpolate the middle integral values of piece-wise smooth function, is investigated. With the help of these splines the problems of mathematical physics in 3-D with respect to one coordinate are reduced to problems for system of equations in 2-D in every layer. This procedure allows reduce also the 2-D problem to a 1-D problem and the solution of the approximated problem can be obtained analytically. As the practical application of the created mathematical mode…
KRYLOV-BOGOLIUBOV APPROACH TO NON-LINEAR HYSTERETIC INSTABILITY IN ROTORDYNAMICS
2012
The internal friction due to the shaft hysteresis or the shrink fitting release exerts a destabilizing effect on the overcritical rotor whirl, but may be counteracted by other external dissipative sources and/or by proper anisotropy of the support stiffness. The internal friction effect may be treated by either dry or viscous models, obtaining similar results in the hypothesis of small dissipation levels, provided that proper equivalence criteria are defined between the two approaches. The equivalence is here stated by imposing the same energy dissipation over a large number of shaft revolutions. Approximate closed-form autonomous solutions for a symmetric rotor arrangement subject to Coulo…
Fluctuations and lack of self-averaging in the kinetics of domain growth
1986
The fluctuations occurring when an initially disordered system is quenched at timet=0 to a state, where in equilibrium it is ordered, are studied with a scaling theory. Both the mean-sizel(t)d of thed-dimensional ordered domains and their fluctuations in size are found to increase with the same power of the time; their relative size fluctuations are independent of the total volumeLd of the system. This lack of self-averaging is tested for both the Ising model and the φ4 model on the square lattice. Both models exhibit the same lawl(t)=(Rt)x withx=1/2, although the φ4 model has “soft walls”. However, spurious results withx≷1/2 are obtained if “bad” pseudorandom numbers are used, and if the n…
γ‐Agregation operators and some aspects of generalized aggregation problem
2010
We explore questions related to the aggregation operators and aggregation of fuzzy sets. No preliminary knowledge of the aggregation operators theory and of the fuzzy sets theory are required, because all necessary information is given in Section 2. Later we introduce a new class of γ‐aggregation operators, which “ignore” arguments less than γ. Due to this property γ‐aggregation operators simplify the aggregation process and extend the area of possible applications. The second part of the paper is devoted to the generalized aggregation problem. We use the definition of generalized aggregation operator, introduced by A. Takaci in [7], and study the pointwise extension of a γ‐agop. First publ…
19F-MRT der Lungenventilation in Atemanhaltetechnik mittels SF6-Gas
2000
Breathhold 19 F-Magnetic Resonance Imaging of Lung Ventilation using SF 6 Gas. Objective: Development of a method to analyze lung ventilation by 19 F-magnetic resonance imaging (MRI) of inspired SF 6 gas during breathhold. Material and Methods: Measurements were performed with a Siemens Magnetom Vision 1.5T scanner using the conventional gradient overdrive. Coronal images of the lung were acquired using ultrafast gradient-echo pulse sequences with TR/TE/α = 1.4 ms/ 0.48 ms/40° without slice selection. With NEX = 200 averages and MA = 32 × 64 raw data matrix, the acquisition time was 9s/image. Higher spatial resolution of 4.7 × 6.3 × 15 mm 3 was obtained with a three-dimensional pulse sequen…
Quantum Hopfield Model
2020
We find the free-energy in the thermodynamic limit of a one-dimensional XY model associated to a system of N qubits. The coupling among the &sigma
A Generalized Missing-Indicator Approach to Regression with Imputed Covariates
2011
We consider estimation of a linear regression model using data where some covariate values are missing but imputations are available to fill in the missing values. This situation generates a tradeoff between bias and precision when estimating the regression parameters of interest. Using only the subsample of complete observations does not cause bias but may imply a substantial loss of precision because the complete cases may be too few. On the other hand, filling in the missing values with imputations may cause bias. We provide the new Stata command gmi, which handles such tradeoff by using either model reduction or Bayesian model averaging techniques in the context of the generalized miss…